#include<iostream>
using namespace std;

class Solution
{
public:
    int trailingZeroes(int n)
    {
        int cnt = 0;
        while (n)
        {
            n /= 5;
            cnt += n;
        }

        return cnt;
    }
};

int main()
{
    Solution s;
    int n = 16;
    int ret=s.trailingZeroes(n);
    cout << ret << endl;
    return 0;
}